Fire extinguishers for generators??

A building contractor is telling me that I need to install a fire extinguisher (properly sized/rated) within the enclosure of my exterior standby-power generator. I cannot find a requirement for this in NFPA 1, NFPA 101, NFPA 110, or NFPA 111. The generator is diesel powered and mounted on top of a UL listed generator base fuel tank.

NFPA 110, would lead me to believe that an extinguisher within this space is not permitted, as it states no items are permitted within the generator enclosure. If there is a code requirement for extinguishers to be within a certain distance of a fixed generator pleas send it me.

I do have the same question that, is there any mandatory requirements are there for suppression system in generator rooms like FOAM/FM200 based on the NFPA standards or we can use Fire extinguishers (portable) and what will be the basis of selection...